The present invention relates to a damping device for a gas turbine combustor, more particularly, to a liner cap to control damping of the gas turbine combustor. The gas turbine combustor comprises a compressor, a liner, a fuel injector, and a combustion chamber. The compressor provides compressed air through the liner, and the fuel injector supplies the combustion chamber with a fuel gas for combustion. The compressed air and the fuel gas are mixed and provided to the combustion chamber, and then the fuel gas is combusted in the combustion chamber. After the combustion, a hot gas generated in the combustion chamber is supplied to a turbine blade of a turbine. However, the combustion of the fuel gas in the combustion chamber also makes a combustion vibration or an acoustic vibration. The acoustic vibration can make a noise, a crack, or a mechanical stress of the gas turbine combustor.
Damping devices have been disclosed for gas turbine combustors to solve the acoustic vibration problem. For example, the damping systems disclosed in U.S. Pat. Nos. 5,575,144 and 5,685,157 provide an external damping device disposed on the outside of the gas turbine combustor and communicating with a case of the gas turbine combustor. However, these damping systems are complex and make the gas turbine combustor bigger.